Many ideas regarding AD&D elves seem to come from Tolkien's Legendarium. Some of these were changed, suggesting they were either misunderstood or deliberately altered.

As in Tolkien, AD&D has several divisions, or subraces of elves:

AD&D Tolkien Differences
High Elves Noldor (aka High Elves)
Gray Elves (aka Faerie) Sindar (aka Grey Elves) In AD&D, Gray Elves are described as 'the rarest and most powerful of their kind', in contrast to the more common High Elves. In most of Tolkien's work, the reverse is really true, with the Noldor being less numerous and more powerful in many ways.
Sylvan/Wood Elves Sylvan/Wood Elves
Half-Elves Half-Elves Half-Elves are rare but prominent in Tolkien's work. They have to choose between being elves, and being mortal humans - those who choose remain as elves seem to resemble elves more than half human/half elves. Numenorians, who founded Gondor, were descended at least partially from the half-elf Elros, and like elves tended to be tall and long lived.
Aquatic Elves No direct equivalent. A group of Tolkien Elves known as the Teleri or Falmari specialize in seafaring and boatbuilding, but were not water breathers.
Dark Elves (aka Drow) No direct equivalent. Tolkien's Elves were divided into the Elves who saw the light of the trees of Valinor (Calaquendi, or light elves) and those who hadn't (the Moriquendi, or dark elves), but the Moriquendi were neither evil, dark skinned or dwellers deep beneath the earth.

Other differences include aging - in AD&D Elves have a lifespan of roughly 1000 years, whereas Tolkien's Elves are essentially unaging - Galadriel and Cirdan were at least 7000 years old at the end of Lord Of The Rings; height - Tolkien's elves tended to be very tall, whereas AD&D elves are shorter than humans.

AD&D elves are also resistant to sleep and charm spells. The sleep resistance may be inspired from Lord Of The Rings - The Two Towers, where Legolas doesn't seem to need sleep while pursuing a group of orcs:

and he could sleep, if sleep it could be called by
Men, resting his mind in the strange paths of elvish dreams, even as he walked
open-eyed in the light of this world.